a digital multimeter with a beeping continuity tester
Available at your local RadioShack.

a garment or a piece of fabric to work on.

a needle or two, a fabric marker or piece of chalk, threads of your choice

a pair of scissors

::Design::

2. Pick out the garment you want to work on and plan the electrical layout of your piece.

If you are using conductive thread, you would want a stiff garment so that the threads of different current (positive side and negative side) do not touch each other. If you are picking out skirts or other garments to make a similar project, make sure they have a good lining in them so that the user would not feel uncomfortable with wires.

Circuit enlarged. Stitching for power (+) is shown in red, ground (-) in black, X in accelerometer in green.

How to Choose LEDs and Power Supply

There are so many different kinds of LEDs, it’s almost mind boggling. In order to get a similar look, you would want to pick Surface Mount LEDs no smaller than 1206. If it’s smaller than 1206, it would be really hard to solder or sew them on to the fabric. When choosing LEDs, make sure you choose the ones that consume less energy. For my project, I used 3.2 forward Voltage – 20 mA- 140 MDC (MDC indicates the brightness. The higher MDC is the brigher the LED will be.)

As for power supply, Lilypad Arduino takes 3.3-5.5V. Choosing something that has similar voltage of your LEDs within that range will save you sometime soldering resistors. For example, if you choose 5 V power supply and your LEDs takes 3.2 V you would need resistors to take down your 5 V to 3.2V. If not, the LEDs will turn on really bright and burn out really fast. For my project, I chose 3.6 V 2200mA Lithium-Polymer battery AA size. It is portable, rechargeable has a lot of Current and just enough Voltage.

Conductive Thread vs. 30-32 AWG Coated WireConductive threads are great for wearable projects. However they have a non- trivial resistance. If you decide to use conductive thread, take desired amount of conductive thread you would use, measure the resistance to see if it has just the right amount. If it has higher resistance than the circuit needs, LEDs will not turn on.

For my project, I chose 30 AWG coated wire which is available at any local Radio Shack at $5. 32 AWG is thinner than 30 AWG but it’s harder to find. These wires have a trivial resistance, and you can tie them up around your Lilypad Arduino instead of soldering them. This is great if you want to keep your Lilypad Arduino clean and in tact. The only drawback is that it might take longer to sew them onto the fabric if you are not used to sewing.

::Construction::

1. Solder two leads to your LEDs whether they are clamping beads or wires

I soldered stripped out 30 AWG wire to my LEDs to make the leads but it could be easier to solder clamping beads to your LEDs. Here are some helpful links to make LED beads.

Left: the multimeter on the continuity testing setting. Right: testing the continuity of a sewn trace.
When two points are connected, the multimeter reads “Shrt” and beeps.

::Programming::

Program your garment.

The way it is set up in my Arduino sketch is this. When the user is standing still no LEDs turn on. Then, according to the acceleration, the harder you dance the more LEDs turn on. Interestingly, you can use pins in Lilypad Arduino as ground if you keep it as digital Low.